The existing washing machines are driven by the motor to bring the washing tub contained laundry to rotate and work properly, and the existing washing machines all have weighing function. There are many ways to realize the weighing function of the washing machine, one way is that the first torque of the motor is measured by controlling the motor to reach the first predetermined rotational speed and rotates the motor at a uniform speed at the first predetermined speed, and then controls the motor to accelerate the motor from the first predetermined rotational speed to the second predetermined rotational speed and measures the rising torque when the motor is raised from the first predetermined rotational speed to the second predetermined rotational speed, and finally controls the motor to rotate at the second predetermined speed uniformly, measures the second torque of the motor at this time and calculate the weight of the laundry in the washing tub according to the change of the torque. One way is that the motor is controlled to reach the first predetermined speed, and then cuts off the power of the motor, detects the number of turns of motor from the power off to still to calculate the weight of the laundry inside the washing tub. Another way is that the motor is controlled to reach the first predetermined speed, and then cuts off the power of the motor and detects the back electromotive force generated after the motor being cut off to calculate the weight of the laundry inside the washing tub.
No matter what kind of way to achieve measurement of the weight of the laundry, they are through motor to measure the weight of the laundry. These measurements are often affected by the type of motor, the tension of the drive belt, the friction of the washing tub system and other conditions, the measurement accuracy is not high, and a lot of situations of wrong judgments. Often a small amount of clothing in the washing machine is measured as a lot of clothing, resulting in a waste of laundry water, and in many times a lot of clothing in the washing tub is measured as a small amount of clothing, resulting in inadequate washing water and clothing are not fully cleaned. This weighing method can only be used as a general reference, besides it also cannot be used as a judge of how much water to be used. Now people are advocating environmental protection, not only to save water, but also less use of detergents, and a best match among clothing, detergent, and washing water is expected, the weighing methods mentioned above are difficult to meet user requirements.
The Chinese patent application No. 201320340304.3 discloses a washing machine with a suspension system which relates to a field of washing machine. The washing machine comprises a housing and a washing tub, wherein, the washing machine comprises a suspension system. The suspension system comprises a suspension foot, a boom, a spring sleeve, a spring, a spring seat, a load cell, and a sensor seat. The suspension system is fixedly connected to the housing through the suspension foot and fixedly connected to the washing tub through the spring sleeve. The boom is arranged on the suspension foot, and the spring sleeve, the spring, the spring seat, the lock cell and the sensor seat are all sleeving on the boom. The spring is mounted between the spring sleeve and the spring seat in a suspended pattern, the load cell is mounted between the spring seat and the sensor seat, the sensor seat is fixedly relative to the boom.
Although the above structure accurately measures the weight of the laundry, there are still the following defects: as the load cell installed in the suspension system, the washing machine components are more complex to install, difficult to track, and security risks are existed. In addition, as the suspension system is mainly used for shock absorption, the washing tub assembly has a bigger vibration during the work process, which results in a larger pressure change of the load cell installed between the spring seat and the sensor seat, and it shortens the service life.
The Chinese patent application No. 201210176786.3 discloses a laundry machine weight sensing device and a method of using the same, which comprises a weighing device installed on the washing machine and a weighing circuit connected to the weighing device. The weighing circuit comprises a microprocessor, a varistor and a voltage dividing protection resistor connected in series with each other and connected to the microprocessor, and is calculated by the change in the resistance value of the varistor. The weighing device is located on upper side of the cover of the housing to facilitate the placement of clothing. The weighing device may be a weighing device such as an electronic balance.
The structure is equivalent to embed the existing electronic balance in the top cover of the housing of the washing machine. Although it is able to measure the weight of clothing, the clothing need to be weighed on the weighing device before each washing and then to be threw into the washing machine to wash, and the user is very troublesome to use. Besides, the device cannot measure the amount of water using in the washing machine.
In the view of foregoing, the present disclosure is proposed.